U.S. patent application number 11/410835 was filed with the patent office on 2006-10-26 for liquid crystal display device.
This patent application is currently assigned to Funai Electric Co., Ltd.. Invention is credited to Takuya Uehara.
Application Number | 20060238481 11/410835 |
Document ID | / |
Family ID | 37111666 |
Filed Date | 2006-10-26 |
United States Patent
Application |
20060238481 |
Kind Code |
A1 |
Uehara; Takuya |
October 26, 2006 |
Liquid crystal display device
Abstract
In an LCD device, a driver circuit board for outputting signals
to source driver ICs and gate driver ICs is placed at a position on
a cover panel distant from a position on the cover panel at which
an inverter control board for cathode ray tubes is placed. The
driver board is connected by first FFCs to a source bus board
having the source ICs mounted thereon, and is further connected by
a second FFC to a gate bus board having the gate ICs mounted
thereon. The second FFC extends via a ridgeline formed between a
top surface and a side surface of a liquid crystal panel. The
signals from the driver board to the gate ICs are provided via the
first FFCs, the source board, the second FFC and the gate board.
This LCD device has improved layout flexibility and facilitates a
change of placement of e.g. a backlight.
Inventors: |
Uehara; Takuya; (Osaka,
JP) |
Correspondence
Address: |
CROWELL & MORING LLP;INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Assignee: |
Funai Electric Co., Ltd.
Daito-Shi
JP
|
Family ID: |
37111666 |
Appl. No.: |
11/410835 |
Filed: |
April 26, 2006 |
Current U.S.
Class: |
345/99 |
Current CPC
Class: |
G02F 1/13452
20130101 |
Class at
Publication: |
345/099 |
International
Class: |
G09G 3/36 20060101
G09G003/36 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 2005 |
JP |
2005-127734 |
Claims
1. A liquid crystal display device comprising: a liquid crystal
panel; a cover panel for covering substantially an entire rear
surface of the liquid crystal panel; a backlight contained in the
cover panel; a film-like source bus board and a film-like gate bus
board which are placed on two adjacent sides of the cover panel;
source driver integrated circuits (hereafter referred to as "ICs")
mounted on the source bus board; gate driver ICs mounted on the
gate bus board; a driver circuit board for controlling timing of
the source driver ICs and the gate driver ICs; a first flexible
cable for connecting the driver circuit board to the source bus
board; and a second flexible cable placed on the two adjacent sides
of the cover panel for connecting the source bus board to the gate
bus board.
2. The liquid crystal display device according to claim 1, wherein
the second flexible cable extends between and is connected to the
source bus board and the gate bus board, extending via a ridgeline
at a corner of the liquid crystal panel formed where the two
adjacent sides of the liquid crystal panel intersect.
3. The liquid crystal display device according to claim 2, which
further comprises an inverter control board placed on the cover
panel for controlling the backlight, wherein the driver circuit
board is placed at a position on the cover panel distant from a
position on the cover panel at which the inverter control board is
placed.
4. The liquid crystal display device according to claim 3, wherein
the inverter control board is placed at a position on the cover
panel near the gate driver ICs.
5. The liquid crystal display device according to claim 4, wherein
control signals sent from the driver circuit board to the source
driver ICs are provided to the source driver ICs via the first
flexible cable and the source bus board, while control signals sent
from the driver circuit board to the gate driver ICs are provided
to the gate driver ICs via the first flexible cable, the source bus
board, the second flexible cable and the gate bus board.
6. The liquid crystal display device according to claim 5, wherein
each of the first flexible cable and the second flexible cable is
an FFC (Flat Flexible Cable).
7. The liquid crystal display device according to claim 1, which
further comprises an inverter control board placed on the cover
panel for controlling the backlight, wherein the driver circuit
board is placed at a position on the cover panel distant from a
position on the cover panel at which the inverter control board is
placed.
8. The liquid crystal display device according to claim 7, wherein
the inverter control board is placed at a position on the cover
panel near the gate driver ICs.
9. The liquid crystal display device according to claim 8, wherein
control signals sent from the driver circuit board to the source
driver ICs are provided to the source driver ICs via the first
flexible cable and the source bus board, while control signals sent
from the driver circuit board to the gate driver ICs are provided
to the gate driver ICs via the first flexible cable, the source bus
board, the second flexible cable and the gate bus board.
10. The liquid crystal display device according to claim 9, wherein
each of the first flexible cable and the second flexible cable is
an FFC (Flat Flexible Cable).
11. The liquid crystal display device according to claim 1, wherein
control signals sent from the driver circuit board to the source
driver ICs are provided to the source driver ICs via the first
flexible cable and the source bus board, while control signals sent
from the driver circuit board to the gate driver ICs are provided
to the gate driver ICs via the first flexible cable, the source bus
board, the second flexible cable and the gate bus board.
12. The liquid crystal display device according to claim 1, wherein
each of the first flexible cable and the second flexible cable is
an FFC (Flat Flexible Cable).
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a liquid crystal display
device, and more particularly to a structure for connecting source
driver ICs and gate driver ICs to a liquid crystal panel, and
connecting a driver circuit board to both the driver ICs to control
their timing.
[0003] 2. Description of the Related Art
[0004] In an active matrix type liquid crystal display (LCD)
device, source terminals connected to source electrodes of thin
film transistors and gate terminals connected to gate electrodes of
the thin film transistors are respectively formed on two adjacent
sides of a liquid crystal panel. The source terminals and the gate
terminals are respectively connected via driver ICs (integrated
circuits) to a driver circuit. The driver circuit provides image
signals and line scan signals (control signals) to the source
terminals and the gate terminals, respectively, by adjusting the
timing of both signals so as to form a predetermined image on a
liquid crystal panel.
[0005] Generally, the driver circuit is connected via bus (cable)
wiring to the respective driver ICs. More specifically, horizontal
and vertical buses in a matrix array for connecting the driver
circuit to the respective driver ICs are provided on a rear surface
of the liquid crystal panel. This will be described in detail below
with reference to FIGS. 3A, 3B and 3C.
[0006] FIGS. 3A, 3B and 3C show a top plan view, a rear view and a
side view, respectively, of a conventional LCD device 51. The LCD
device 51 comprises: a liquid crystal panel 52; a metal-made cover
panel 53 for covering substantially the entire rear surface of the
liquid crystal panel 52; a backlight contained in the cover panel
53 and comprised of U-shaped cathode ray tubes 54; source driver
ICs 55 provided on a top surface 52a of the liquid crystal panel 52
and connected to the liquid crystal panel 52; gate driver ICs 56
provided on a side surface 52b of the liquid crystal panel 52 and
connected to the liquid crystal panel 52; a source bus board 57
connected to the source driver ICs 55; and a gate bus board 58
connected to the gate driver ICs 56. These source bus board 57 and
gate bus board 58 are connected to a driver circuit board 59 placed
and fixed on the cover panel 53 via FFCs (Flat Flexible Cables) 61
and 62, respectively. Further, an inverter control board 63 for
controlling the cathode ray tubes 54 is fixed on the cover panel
53. Note that generally the inverter control board 63 is placed in
an above-center position on the cover panel 53, because the
brightness of the entire screen based on the cathode ray tubes 54
can be more easily controlled by applying the inverter control to
upper ones of the cathode ray tubes 54.
[0007] Since the source bus board 57 and the gate bus board 58 are
provided on the top surface 52a and the side surface 52b,
respectively, of the liquid crystal panel 52, it is a natural
consequence that the FFCs 61 connecting the source bus board 57 to
the driver circuit board 59 and the FFC 62 connecting the gate bus
board 58 to the driver circuit board 59 are respectively provided
to extend vertically and horizontally on or over the cover panel
53. Thus, a most efficient position of the driver circuit board 59
is an upper right position on the cover panel 53 in the rear view
as shown in FIG. 3B. However, at the same time, the possible
position of the driver circuit board 59 is substantially limited to
such upper right position on the cover panel 53, resulting in poor
layout flexibility, for the following reason.
[0008] For example, when the U-shaped cathode ray tubes 54 in the
LCD device 1 are reversed left to right for the purpose of making
uniform the brightness of the screen or for other purposes, then
connectors 54a of the cathode ray tubes 54 are positioned on the
right side in FIG. 3B. Thus, it becomes necessary to place the
inverter control board 63 in a right-of-center position on the
cover panel 53. In this case, if the driver circuit board 59 is
placed in a left-of-center position on the cover panel 53 in order
to avoid interference between the driver circuit board 59 and the
inverter control board 63, the FFC 62 extending horizontally to
connect the driver circuit board 59 to the gate bus board 58
becomes very long, making it troublesome to handle. In addition, in
such case, the FFC 62 either passes near or straddles the inverter
control board 63, so that there is a possibility that noise is
superimposed on the signals sent from the driver circuit board 59
to the gate driver ICs 56 via the FFC 62.
[0009] There are known technologies of LCD devices, which use
flexible connections to connect a driver circuit to driver ICs. For
example, Japanese Laid-open Patent Publication 2004-4924 (Japanese
Patent 3575482) discloses to use flexible circuit boards to
facilitate assembly when connecting driver ICs to a driver circuit,
in which at least two flexible circuit boards are required for
sources and gates. For cable connection between the two or more
flexible circuit boards, this Patent Publication teaches to provide
wiring connections between two adjacent flexible circuit boards
positioned perpendicular to each other and provided on two adjacent
intersecting sides of a liquid crystal panel.
[0010] On the other hand, Japanese Laid-open Patent Publication Hei
1-234829 (Japanese Patent 2504106) discloses to use film-like
connecting members to connect driver circuit modules having driver
ICs to sides of a liquid crystal panel of an LCD device. Because of
the use of the film-like connecting members, the driver circuit
modules can be placed on side surfaces of the liquid crystal panel
which are perpendicular to the main surface of the liquid crystal
panel. This prevents the LCD device from having a very large outer
size due to the driver circuit modules.
[0011] However, such known technologies as disclosed in these
Patent Publications do not lead to a solution to improve layout
flexibility of laying out elements in an LCD device such as a
driver circuit board and an inverter control board, or to
facilitate a change of placement of e.g. a backlight.
SUMMARY OF THE INVENTION
[0012] An object of the present invention is to provide an LCD
device that is improved in structure for connecting a driver
circuit board to source driver ICs and gate driver ICs so as to
improve layout flexibility and facilitate a change of placement of
e.g. a backlight.
[0013] According to the present invention, this object is achieved
by a liquid crystal display device comprising: a liquid crystal
panel; a cover panel for covering substantially an entire rear
surface of the liquid crystal panel; a backlight contained in the
cover panel; a film-like source bus board and a film-like gate bus
board which are placed on two adjacent sides of the cover panel;
source driver integrated circuits (hereafter referred to as "ICs")
mounted on the source bus board; gate driver ICs mounted on the
gate bus board; a driver circuit board for controlling timing of
the source driver ICs and the gate driver ICs; a first flexible
cable for connecting the driver circuit board to the source bus
board; and a second flexible cable placed-on the two adjacent sides
of the cover panel for connecting the source bus board to the gate
bus board.
[0014] According to the present invention, the flexibility of
layout (flexibility of positions to place respective components) is
improved, facilitating a design such as a change of placement of
e.g. a backlight in an LCD device which comprises: a liquid crystal
panel; a cover panel for covering substantially the entire rear
surface of the liquid crystal panel; a backlight contained in the
cover panel; source driver ICs and gate driver ICs connected to the
liquid crystal panel on two adjacent sides of the liquid crystal
panel, respectively; and a driver circuit board connected to both
driver ICs via bus wirings, respectively. Furthermore, the
connection structure can be simplified, resulting in a higher
probability of reducing manufacturing cost.
[0015] Preferably, the second flexible cable extends between and is
connected to the source bus board and the gate bus board, extending
via a ridgeline at a corner of the liquid crystal panel formed
where the two adjacent sides of the liquid crystal panel
intersect.
[0016] Further preferably, the liquid crystal display device
further comprises an inverter control board placed on the cover
panel for controlling the backlight, wherein the driver circuit
board is placed at a position on the cover panel distant from a
position on the cover panel at which the inverter control board is
placed.
[0017] While the novel features of the present invention are set
forth in the appended claims, the present invention will be better
understood from the following detailed description taken in
conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention will be described hereinafter with
reference to the annexed drawings. It is to be noted that all the
drawings are shown for the purpose of illustrating the technical
concept of the present invention or embodiments thereof,
wherein:
[0019] FIGS. 1A, 1B and 1C are a top plan view, a rear view and a
side view, respectively, of a liquid crystal display (LCD) device
according to an embodiment of the present invention;
[0020] FIG. 2 is a perspective view of a portion of the LCD device
in the case where a top surface and a side surface of a cover panel
intersect at, and thereby form, a tilted ridgeline; and
[0021] FIGS. 3A, 3B and 3C are a top plan view, a rear view and a
side view, respectively, of a conventional LCD.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] The best modes and preferred embodiments of the present
invention will be described hereinafter with reference to the
annexed drawings. The specific embodiments described are not
intended to cover the entire scope of the present invention, and
hence the present invention is not limited to only the specific
embodiments. Note that like parts are designated by like reference
numerals or reference characters throughout the drawings.
[0023] Referring to FIGS. 1A, 1B and 1C, a liquid crystal display
(LCD) device 1 according to an embodiment of the present invention
will be described. FIGS. 1A, 1B and 1C show a top plan view, a rear
view and a side view, respectively, of the LCD device 1. The LCD
device 1 comprises: a liquid crystal panel 2; a metal-made cover
panel 3 for covering substantially the entire rear surface of the
liquid crystal panel 2; a backlight contained in the cover panel 3
and comprised of U-shaped cathode ray tubes 4; source driver ICs 5
provided on a top surface 2a of the liquid crystal panel 2 and
connected to the liquid crystal panel 2; gate driver ICs 6 provided
on a side surface 2b of the liquid crystal panel 2 and connected to
the liquid crystal panel 2; a source bus board 7 having the source
driver ICs 5 mounted thereon and connected thereto; and a gate bus
board 8 having the gate driver ICs 6 mounted thereon and connected
thereto.
[0024] The source bus board 7 and the gate bus board 8 are formed
of flexible boards with source bus and gate bus provided thereon,
respectively. Each of the flexible boards is an elongated
rectangular-shaped and film-like board, which is generally referred
to as an FPC (Flexible Printed Circuit). The source driver ICs 5
and the gate driver ICs 6 are respectively mounted on and connected
to the source bus board 7 and the gate bus board 8 by so-called TAB
(Tape Automated Bonding) or COF (Chip on Film). The source bus
board 7 and the gate bus board 8 are placed on two adjacent sides
of the cover panel 3. More specifically, the source bus board 7 and
the gate bus board 8 are in intimate contact with and along a top
surface 3a and a side surface 3b, respectively, of the cover panel
3. Note that since the source driver ICs 5 and the gate driver ICs
6 formed by the TAB or COF become more expensive in proportion to
the lengths of the flexible boards, it is desirable to reduce the
lengths of the flexible boards.
[0025] In the LCD device 1 of the present embodiment, the cathode
ray tubes 4 are placed such that connectors 4a of the cathode ray
tubes 4 are positioned on the right side in the rear view as shown
in FIG. 1B, while an inverter control board 9 for controlling the
cathode ray tubes 4 is placed and fixed at an upper right position,
in the rear view as shown in FIG. 1B, on a major surface 3c of the
cover panel 3 which is on the rear side or rear surface of the LCD
device. The inverter control board 9 is placed at a position on the
cover panel 3 near the gate driver ICs 6. Further, a driver circuit
board 11 for sending signals to the source driver ICs 5 and the
gate driver ICs 6 is placed at a left upper position on the major
surface 3c of the cover panel 3 to avoid interference between the
inverter control board 9 and connection wirings 12 which connect
the inverter control board 9 to the cathode ray tubes 4.
[0026] The driver circuit board 11 controls timing of the source
driver ICs 5 and the gate driver ICs 6, more specifically adjusts
timing of image signals and line scan signals (control signals),
and provides the timing-adjusted image signals and line scan
signals to the source driver ICs 5 and the gate driver ICs 6,
respectively, so as to form a predetermined image on a screen of
the liquid crystal panel 2. The following describes a structure for
connecting the driver circuit board 11 to the respective driver ICs
5 and 6.
[0027] Two first flexible cables (Flat Flexible Cables, hereafter
referred to as FFCs) 13 extend between and are connected to the
driver circuit board 11 and the source bus board 7, extending via a
ridgeline L1 at a corner of the liquid crystal panel 2 formed where
the adjacent top surface 3a and major surface 3c of the cover panel
3 intersect. On the other hand, a second flexible cable (FFC) 14
extends between and is connected to the source bus board 7 and the
gate bus board 8, extending via a further ridgeline L2 at a further
corner of the liquid crystal panel 2 formed where the adjacent top
surface 2a and side surface 2b of the liquid crystal panel 2
intersect, and where the adjacent top surface 3a and side surface
3b of the cover panel 3 intersect. Since the first FFCs 13 and the
second FFC 14 all have sufficient flexibility, they can be placed
on and along the respective surfaces of the LCD device 1 via the
ridgelines L1 and L2 without difficulty.
[0028] More specifically, despite the existence of the ridgelines
L1 and L2 at the comers of the liquid crystal panel 2 or the cover
panel 3, the first FFCs 13 are in contact with the major surface 3c
and top surface 3a of the cover panel 3 via the ridgeline L1, while
the second FFC 14 is in contact with the top surface 2a and side
surface 2b of the liquid crystal panel 2, as well as the top
surface 3a and side surface 3b of the cover panel 3, via the
ridgeline L2. This is due to the flexibility of the first and
second FFCs 13 and 14. Besides, note that although two of the first
FFCs 13 are used here to provide e.g. images signals and, line scan
signals (control signals) from the driver circuit board 11 to the
source bus board 7, it can be readily devised as one first FFC (one
first flexible cable) for the same purpose.
[0029] Further note that if the backlight has a large structure to
cause the thickness (front-to-rear width) of the cover panel 3 to
be large, the entire cover panel 3 may become trapezoidal in shape.
FIG. 2 is a perspective view of a portion of an LCD device 1 in the
case where a top surface 3a and a side surface 3b of a cover panel
3 intersect at, and thereby form, a ridgeline L2t which is tilted
from an original ridgeline L2 formed between a top surface 2a and a
side surface 2b of a liquid crystal panel 2. As shown in FIG. 2,
for example, the ridgeline L2t between the adjacent top surface 3a
and side surface 3b of the cover panel 3 may be tilted from the
original ridgeline L2. However, even in this case, a second FFC 14
can be placed on and along the top surface 3a and side surface 3b
of the cover panel 3 via the ridgeline L2t without difficulty,
since the second FFC 14 has sufficient flexibility.
[0030] Referring back to FIGS. 1A to 1C, e.g. the image signals
sent or provided from the driver circuit board 11 are input to the
source driver ICs 5 via the first FFCs 13 and the source bus board
7, while e.g. the line scan signals sent or provided from the
driver circuit board 11 are input to the gate driver ICs 6 via the
first FFCs 13, the source bus board 7, the second FFC 14 and the
gate bus board 8. Thus, the control signals input from the driver
circuit board 11 to the gate driver ICs 6 pass through paths
sufficiently distant from the inverter control board 9 and from the
connection wirings 12 which connect the inverter control board 9 to
the cathode ray tubes 4. Accordingly, there is little possibility
that noise is superimposed from e.g. the inverter control board 9
and the connection wirings 12 onto the control signals sent from
the driver circuit board 11 so as to degrade the control signals.
Besides, the inverter control board 9 can be placed at a position
on the cover panel 3 near the gate driver ICs 6.
[0031] As described above, the electrical connection from the
driver circuit board 11 to the bus boards 7 and 8 is made via the
first FFCs 13 (first flexible cable), forming a single or only
output path from the major surface 3c of the cover panel 3, and
extending vertically to the ridgeline L1 along the major surface 3c
of the cover panel 3. Thus, signals to be provided from the driver
circuit board 11 to the gate bus board 8 are also once output
through the first FFCs 13, more specifically, through the first
FFCs 13, the source bus board 7 and the second FFC 14. That is, the
electrical connection from the source bus board 7 to the gate bus
board 8 is made via the second FFC 14.
[0032] Accordingly, the driver circuit board 11 can be easily
placed at an optional position on the major surface 3c of the cover
panel 3. In the case of the example described above, even though
the inverter control board 9 for controlling the cathode ray tubes
4 is placed at an upper right position of the cover panel 3, the
driver circuit board 11 can be placed at an optional upper left
position on the major surface 3c of the cover panel 3 without any
need to consider the signal transmission path from the driver
circuit board 11 to the gate driver ICs 6. Furthermore, the
connection structure according to the present embodiment enables
simple wiring connections, reducing manufacturing cost.
[0033] It is to be noted that the present invention is not limited
to the above embodiments, and various modifications are possible.
For example, flexible cables (cables having flexibility) such as
FPCs other than FFCs can be used for the first FFCs (or FFC) 13 to
connect the driver circuit board 11 to the source bus board 7, and
for the second FFC 14 to connect the source bus board 7 to the gate
bus board 8. Further, in addition to the function of outputting
signals to the source driver ICs 5 and gate driver ICs 6 by
adjusting the timing of both signals, the driver circuit board 11
can have a function of generating image signals to be output to the
source driver ICs 5. In short, the driver circuit board 11 can be a
circuit board which is connected in common to the source driver ICs
5 and the gate driver ICs 6, and which has a function of outputting
timing control signals to both driver ICs 5 and 6.
[0034] The present invention has been described above using
presently preferred embodiments, but such description should not be
interpreted as limiting the present invention. Various
modifications will become obvious, evident or apparent to those
ordinarily skilled in the art, who have read the description.
Accordingly, the appended claims should be interpreted to cover all
modifications and alterations which fall within the spirit and
scope of the present invention.
[0035] This application is based on Japanese patent application
2005-127734 filed Apr. 26, 2005, the content of which is hereby
incorporated by reference.
* * * * *